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Mechanical recycling of PET containing mixtures of phosphorus flame retardants

Journal of materials science & technology 2024年第27期194卷 167-179页

作者： Jiuke Chen Sithiprumnea Dul Sandro Lehner Milijana Jovic Sabyasachi Gaan Manfred Heuberger Rudolf Hufenus Ali Gooneie Empa Swiss Federal Laboratories for Materials Science and TechnologyLaboratory of Advanced FibersSt.GallenSwitzerland ETH Zurich Department of MaterialsSwitzerland Circular Plastics Department of Circular Chemical EngineeringFaculty of Science and EngineeringMaastricht UniversityUrmonderbaan 226162 AL GeleenThe Netherlands

Flame-retarded polymers,such as polyester textiles and sheets,are attracting attention with regard to their *** recycling is currently the most frequently used technique for improving the circularity of ***,one complication of mechanical recycling is associated with the(still)inevitable mixtures of polymers and additives,which can influence material stability and significantly de-teriorate the mechanical properties of recycled *** this study,we aim to specifically investigate the interactions between mixtures of phosphorus flame retardants(FRs)in polyethylene terephthalate(PET)and evaluate their potential role in the mechanical recycling of melt-spun *** highly rel-evant commercial FRs,namely a DOPO-derivative(DOPO-PEPA or DP)and Aflammit PCO 900(AF),are added to PET compounds as additives using a melt *** melt stability of PET/FR compounds over extended processing time is assessed by chemical,thermal,and rheological *** shows a molecular lubrication effect,lowering the melt viscosity of PET,while AF promotes chemical changes(i.e.,chain branching/crosslinking).Interestingly,a PET compound containing hybrid mixtures of DP/AF 20/80(wt.%/wt.%)shows the most stable behavior at high temperatures under both nitrogen and air at-mospheres,thus showing a synergistic *** importantly,in a recycling scenario,the stabilization effect persists at diluted concentrations below the typical FR contents in *** extrusion cycles are used to assess the repeated processing behavior of the compounds,and the mechanical properties and fire behavior of melt-spun fibers are compared before and after *** results reveal that DP can maintain the mechanical performance of recycled PET/FR fibers,even if it is mixed(contaminated)with AF.

关键词： PET Mechanical recycling Melt spinning Phosphorus flame retardant

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Precipitation Behavior of MnS Inclusion in Unidirectionally-solidified Fe–18Mn–1Al–0.3C Steels

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Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan 2025年第3期111卷 122-130页

作者： Fan, Yuewen Kameda, Kouki Hu, Xiaojun Matsuura, Hiroyuki State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing China Department of Materials Engineering Graduate School of Engineering The University of Tokyo Japan

In order to reasonably control the precipitation of inclusions during solidification in TWIP steels, the precipitation behavior of typical MnS inclusions in high manganese steel was investigated by unidirectional solidification experiments. Through the combined analyses using ASEM-EDS, optical microscope, and thermodynamic calculation, it was found that Mn concentration in the liquid metal region were higher than those in the solid metal region. Furthermore, closer to the inclusion the liquid phase was, higher its Mn content was. In Fe–18mass%Mn–1Al–0.3C, MnS inclusions can precipitate at the positions located in the junction of dendrites at the end of the solidification (solid fraction fS = 0.96), Mn content reaching 34.88 mass%. Already existing Al2O3 particles could become the core of MnS to form composite inclusions to promote the MnS precipitation during the solidification process. When fS achieved 0.7 leading the Mn segregation in the liquid phase to 25 mass%, MnS starts to precipitate to attach the Al2O3 surface to form composite inclusion. © 2025 The Iron and Steel Institute of Japan.

关键词： Manganese steel

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Development of the high-strength ductile ferritic alloys via regulating the intragranular and grain boundary precipitation of G-phase

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Journal of materials science & technology 2023年第5期136卷 180-199页

作者： Mujin Yang Chao Huang Jiajia Han Haichen Wu Yilu Zhao Tao Yang Shenbao Jin Chenglei Wang Zhou Li Ruiying Shu Cuiping Wang Huanming Lu Gang Sha Xingjun Liu School of Materials Science and Engineering Harbin Institute of TechnologyShenzhen 518055China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China College of Materials and Fujian Provincial Key Laboratory of Materials Genome Xiamen UniversityXiamen 361005China Test Center Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Department of Materials Science and Engineering City University of Hong KongHong KongChina Department of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyShenzhen 150001China Institute of Materials Genome and Big Data Harbin Institute of TechnologyShenzhen 518055China

A typical G-phase strengthened ferritic model alloy(1Ti:Fe-20Cr-3Ni-1Ti-3Si,wt.%)has been carefully studied using both advanced experimental(EBSD,TEM and APT)and theoretical(DFT)*** the classic“solid solution and aging”process,the superfine(Fe,Ni)_(2)TiSi-L2_(1)particles densely precipitate within the ferritic grain and subsequently transform into the(Ni,Fe)_(16)Ti_(6)Si_(7)-G *** the meanwhile,the elemental segregation at grain boundaries and the resulting precipitation of a large amount of the(Ni,Fe)_(16)Ti_(6)Si_(7)-G phase are also *** nanoscale microstructural evolutions result in a remarkable increase in hardness(100-300 HV)and severe *** the“cold rolling and aging”process is used,the brittle fracture is effectively suppressed without loss of nano-precipitation strengthening *** yield strength of 1700 MPa with 4%elongation at break is *** key improvement in mechanical properties is mainly attributed to the pre-cold rolling process which effectively avoids the dense precipitation of the G-phase at the grain *** findings could shed light on the further exploration of the precipitation site via optimal processing strategies.

关键词： G-phase Precipitation strengthening Grain boundary segregation Nano-precipitates

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Enabling simultaneous reprocessability and fire protection via incorporation of phosphine oxide monomer in epoxy vitrimer

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Journal of materials science & technology 2024年第29期196卷 224-236页

作者： Zhenyu Huang Wenyu Wu Klingler Daniele Roncucci Carolina Polisi Valentin Rougier Sandro Lehner Milijana Jovic Daniel Rentsch Sithiprumnea Dul Karin Brändli Hedlund Véronique Michaud Zhengzhou Wang Sabyasachi Gaan Department of Polymeric Materials School of Materials Science and EngineeringTongji UniversityShanghai201804China Laboratory for Advanced Fibers Empa Swiss Federal Laboratories for Materials Science and TechnologyLerchenfeldstrasse 5St.Gallen9014Switzerland Laboratory for Processing of Advanced Composites(LPAC) Ecole Polytechnique Fédérale de Lausanne(EPFL)1015 LausanneSwitzerland Laboratory for Functional Polymers Empa Swiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 1298600 DübendorfSwitzerland Institute for Materials technology and plastics processing OST-Eastern Switzerland University of Applied Sciences8640 RapperswilSwitzerland Key Laboratory of Advanced Civil Engineering Materials Tongji UniversityShanghai201804China

The conception of epoxy thermosets with both reprocessability and flame retardancy delineates a new horizon in polymer science,offering a material solution that is not only superior in fire safety but is also environment ***,a flame-retardant epoxy vitrimer(EV)was prepared using partially bio-based IADPPO(diphenylphosphine oxide itaconic anhydride)and citric acid as curing reagents via a solvent-free *** incorporation created covalent adaptable networks(CANs)in the matrix which promote reprocessability and *** EV exhibits excellent thermal stability with high initial decomposition temperature(T_(- 5wt%)∼308℃)and high glass transition temperature(T_(g)∼107℃),similar to the blank EV(115℃).The flame retardancy,mechanical properties,transesterification-based reprocessability,and flame-retardant mechanism were *** EV containing 3 wt%phosphorus(EV IADPPO 3P)achieved UL-94 V0 classification with a limiting oxygen index(LOI)of 27%,while the virgin sample Blank EV(without phosphorus)burned ***,increased flexural strength of 79%was observed for EV IADPPO 3P compared to Blank ***,the flame-retardant EV showed high malleability and reparability that could be thermomechanically reprocessed without sacrificing the thermal,mechanical,and flame-retardant ***,the newly developed epoxy vitrimer is not only fire-safe but fulfills the sustainability goals of today’s society.

关键词： Epoxy vitrimer Covalent adaptable networks Flame retardancy Reparable and reprocessable Bio-based thermoset

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Relationship between the unique microstructures and behaviors of high-entropy alloys

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International Journal of Minerals,Metallurgy and materials 2024年第6期31卷 1350-1363页

作者： Yaqi Wu Peter KLiaw Ruixuan Li Weiran Zhang Guihong Geng Xuehui Yan Guiqun Liu Yong Zhang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA Xi’an Rare Metal Materials Institute Co.Ltd. Xi’an 710016China School of Materials Science and Engineering North Minzu UniversityYinchuan 750030China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China

High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous ***,in this context,can be perceived as representing disorder and *** contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as *** accordance with Shannon entropy,structure is analogous to ***,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its *** addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural *** profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous *** features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion *** this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.

关键词： high-entropy alloys unique microstructure special properties alloy design

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Coalescence of Al_(0.3)CoCrFeNi polycrystalline high-entropy alloy in hot-pressed sintering: a molecular dynamics and phase- field study

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npj Computational materials 2023年第1期9卷 424-436页

作者： Qingwei Guo Hua Hou Kaile Wang Muxi Li Peter K.Liaw Yuhong Zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan 030051P R China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024P R China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTNUSA Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083P R China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004P R China

Existing hot sintering models based on molecular dynamics focus on single-crystal *** work proposes a new multiparticle model based on molecular dynamics to investigate coalescence kinetics during the hot-pressed sintering of a polycrystalline Al_(0.3)CoCrFeNi high-entropy *** accuracy and effectiveness of the multiparticle model are verified by a phase-field *** this model,it is found that when the particle contact zones undergo pressure-induced evolution into exponential power creep zones,the occurrences of phenomena,such as necking,pore formation/filling,dislocation accumulation/decomposition,and particle rotation/rearrangement are *** on tensile test results,Young’s modulus of the as-sintered Al_(0.3)CoCrFeNi high-entropy alloy is calculated to be 214.11±1.03 GPa,which deviates only 0.82%from the experimental value,thus further validating the feasibility and accuracy of the multiparticle model.

关键词： alloy creep entropy

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Construction of multi-homojunction TiO_(2)nanotubes for boosting photocatalytic hydrogen evolution by steering photogenerated charge transfer

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Nano Research 2023年第2期16卷 2259-2270页

作者： Jinbo Xue Shan Jiang Chengkun Lei Huan Chang Jiaqi Gao Xuguang Liu Qi Li Qianqian Shen Key Laboratory of Interface Science and Engineering in Advanced Materials(Taiyuan University of Technology) Ministry of EducationTaiyuan 030024China Department of Chemistry Tsinghua UniversityBeijing 100084China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China

As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide ***,we reported a simple and robust method to construct multi-homojunctions in black TiO_(2) nanotubes by the gradient doping of Ni species through the diffusion of deposited Ni element on the top of black TiO2 nanotubes driven by a high temperature annealing *** gradient Ni distribution created parts of different Fermi energy levels and energy band structures within the same black TiO_(2) nanotube,which subsequently formed two series of multi-homojunctions within *** special multi-homojunction structure largely enhanced the charge carrier separation and transportation,while the low concentration of defect states near the surface layer further inhibited carrier recombination and facilitated the surface ***,the B-TNT-2Ni sample with the optimized Ni doping concentration exhibited an enhanced hydrogen evolution rate of~1.84 mmol·g^(−1)·h^(−1)under visible light irradiation without the assistance of noble-metal cocatalysts,~four times higher than that of the pristine black TiO_(2)nanotube *** the capability to create multi-homojunction structures,this approach could be readily applied to various dopant systems and catalyst materials for a broad range of technical applications.

关键词： Ni gradient-doped TiO_(2) multi-homogeneous junction energy band bending directional built-in electric field photocatalytic H_(2)evolution

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Optimization of porosity behavior of hybrid reinforced titanium metal matrix composite through RSM, ANN, and GA for multi-objective parameters

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Journal of engineering and Applied science 2024年第1期71卷 1-34页

作者： Gemeda, Birhane Assefa Sinha, Devendra Kumar Mengesha, Getinet Asrat Gautam, Satyam Shivam Mechanical Engineering Department School of Mechanical Chemical and Materials Engineering Center of Excellence Advanced Manufcaturing Engineering Adama Science & ampTechnology University Adama Ethiopia Department of Materials Science and Engineering Adama Science & ampTechnology University Adama Ethiopia Mechanical Engineering Department North Eastern Regional Institute of Science and Technology Arunachal Pradesh Itanagar791109 India

Titanium matrix composites (TMCs) have high specific strength and stiffness, and high-temperature TMCs can reduce weight by up to 50% when compared with monolithic super alloys while preserving equal stiffness and strength in jet engine systems for propulsion. The purpose of this work examines the use of mathematical models and learning approaches to optimize response such as porosity and control variables in synthesized hybrid titanium metal matrix composites (HTMMCs) reinforced by B4C-SiC-MoS2-ZrO2. To further understand the impacts of process factors on porosity reduction, the study employs methodologies such as the response surface methodology (RSM), integrated artificial neural networks (ANN), and genetic algorithm (GA). The findings indicate that these strategies have the potential to contribute to the industry. The optimal combination of 7.5wt.% SiC, 7.5wt.% B4C, 7.5wt.% ZrO2, 4wt.% MoS2, and 73.5wt.% Ti compositions was determined utilizing process factors such as milling period (6h), compaction pressure (50MPa), compact duration (50min), sintering temperature (1200°C), and sintering time (2h) as compared to pure Ti grade 5. The mechanical properties of the optimum combination of reinforcement weight percentage and process parameters resulted in a minimum porosity of 0.118%, density of 4.36gcm3, and micro-hardness of 63.4HRC boosted by 1.76%, and compressive strength of 2500MPa increased by 2.6%. In addition, these HTMMCs had a minimal wear rate of 0.176mm3/Nm and a corrosion resistance rate of 2.15×10-4mmpy. The investigation result analysis discovered that the RSM and combined ANN-GA models considerably enhanced the forecasting of multidimensional interaction difficulties in composite material production that were highly statistically connected, with R2 values of 0.9552 and 0.97984. The ANN-GA model provided a 95% confidence range for porosity predictions, which increased the production use of titanium-based particle composites. Furthermore, HMMCs can be u

关键词： Porosity

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Effect of initial orientation on microstructure and mechanical properties of AZ31 Mg alloy sheets via accumulated extrusion bonding

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Progress in Natural science:materials International 2023年第2期33卷 178-184页

作者： Xia Cao Tingzhuang Han Ji Xu Guangsheng Huang Hua Zhang Jianhui Bai Fusheng Pan Department of Mechanics and Surface Engineering Changzhou Institute of Technology Department of Aviation Manufacturing Engineering Changzhou Institute of Technology State Key Laboratory of Solidification Processing School of Materials Science & Engineering Northwestern Polytechnical University State Key Laboratory of Mechanical Transmission College of Materials Science and Engineering Chongqing University Institute for Advanced Studies in Precision Materials Yantai University

In this study, effects of initial orientation on microstructure evolution and mechanical properties of AZ31 Mg alloy sheets via accumulated extrusion bonding(AEB) was systematically studied. The samples with RD and TD parallel to extrusion direction(ED) were labeled as RED and TED, respectively. RD and TD pieces alternately stacked was named as RTED. The results revealed that under three-dimensional compressive stress, {10-12} tensile twinning dominated the first stage deformation in container. As the plunger continuous press down, dynamic recrystallization(DRX) occurred, and the newly fine DRXed grains along original and twin grain boundaries gradually consumed the matrix and twin grains. The microstructure was completely transformed into recrystallized grain structure at sizing band with an average grain size of ～0.9 μm in TED sample, smaller than that of RED *** the alloys extruded out of the die, DRXed grains significantly grew to ～4.5 μm and 3.5 μm for RED and TED samples, respectively. A laminated microstructure was obtained with average grain sizes of～4.4 μm in RD layers and 3.5 μm in TD layers for RTED sample. The AEB processed samples exhibited an ED-tilt double-peak basal texture with similar texture intensity. The tensile tests results indicated that attributed to the combined effect of grain refinement and texture evolution, the yield strength and fracture elongation of RED and TED samples was significantly improved. The heterogeneous microstructure in RTED sample induced an extra work hardening(HDI-work hardening) in tensile deformation and resulted in a further improved elongation of 32.0%.

关键词： Magnesium alloy Accumulated extrusion bonding Initial orientation Microstructure Texture Mechanical properties

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PERFORMANCE EVALUATION OF HONEYCOMB FOAM CORE HYBRID SANDWICH COMPOSITES WITH VARYING FIBER REINFORCED POLYMER SKIN

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Composites: Mechanics, Computations, Applications 2024年第1期15卷 65-78页

作者： Kamaraj, M. Matthew, Samuel Navghare, Sarvesh Datta, Shubhabrata Centre for Composite and Advanced Materials Department of Mechanical Engineering Faculty of Engineering and Technology SRM Institute of Science and Technology Kattankulathur Tamil Nadu Chengalpattu603203 India

This research is an analysis of a unique high-density honeycomb foam named Lantor Soric, a flexible core material specifically used for resin infusion. To understand the full scope of this unique core material, it was bonded with various synthetic, natural, and hybrid face sheets. The glass, carbon, and jute fibers were utilized to prepare the face sheets, and epoxy was used as a binder. The sandwich composite samples were developed by a vacuum resin infusion technique. The performance of the sandwich composite, such as water absorption, flammability, and tensile and flexural strength, revealed that the addition of honeycomb foam to the composite structure improved the performance, such as water absorption, flammability, and tensile and flexural strength of the sandwich composite. The honeycomb foam was able to distribute the resin evenly throughout the laminate via its flow channels. Also, the hybrid composite of natural and synthetic fibers showed some astonishing properties in mechanical testing. The failure mechanism of the sandwich composite was inspected using scanning electron microscopy. Fractography revealed that the main mechanism for the failure was fiber pull out, voids, and interfacial debonding. © 2024 by Begell House, Inc. ***.

关键词： Foams

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